<html>
<head>
    <title>Hello</title>
    <style>
    h1 {
        color: #333333;
        font-size: 48px;
        text-shadow: 3px 3px 3px #666666;
    }
    </style>
    <script>
        function change() {
            document.getElementsByTagName('h1')[0].style.color='#ff0000';
        }
    </script>
</head>
<body>
    <h1 onclick="change()">Hello, world!</h1>
</body>
</html>